IC50 for competition curves and FRET homotransfer
IC50 were determined by competition binding and FRET homotransfer, as described under Materials and Methods and in legends to Figs. 3 and 5. F and F0 are the net fluorescence of the hNPRA-ECD-AF-488 homodimer in the presence of the highest concentration of peptide or in its absence, respectively. Values are mean ± S.E. of three to four separate experiments (indicated in parentheses), with each measurement done in duplicate or quadruplicate, for binding and quenching, respectively. There was a high correlation (r = 0.99; p < 0.002) between the log of IC50 from binding assays and those from fluorescence quenching studies
Peptide | Radioligand Binding IC50 | Fluorescence Quenching | ||
|---|---|---|---|---|
| IC50 | F/F0 (max) | |||
| M | ||||
| BANP | 2.72 ± 0.13 × 10−10 (3) | 4.27 ± 0.52 × 10−10 (3) | 0.77 ± 0.03 (3) | |
| rANP 1-28 | 1.77 ± 0.18 × 10−9 (4) | 3.10 ± 0.72 × 10−9 (4) | 0.80 ± 0.03 (4) | |
| Mini-ANP | 1.52 ± 0.11 × 10−8 (3) | 2.18 ± 0.32 × 10−8 (3) | 0.75 ± 0.01 (3)* | |
| pBNP32 | 1.64 ± 0.10 × 10−8 (3) | 7.70 ± 0.39 × 10−9 (3) | 0.66 ± 0.01 (3)** | |
| A71915 | 1.04 ± 0.14 × 10−6 (3) | 6.10 ± 0.99 × 10−7 (3) | 0.60 ± 0.02 (3)** | |
| C-ANF | >10−5 (3) | >10−5 (3) | N.D. | |
| CNP-22 | >10−5 (3) | >10−5 (3) | N.D. | |